Most health guidelines don’t frame fish intake as a daily target. Instead, the standard recommendation is 2 to 3 servings per week, which works out to roughly 8 to 12 ounces total. If you prefer to think in daily terms, that’s about 1.1 to 1.7 ounces per day, or a palm-sized portion every two to three days. A single serving is 3 ounces cooked, roughly the size of a deck of cards or three-quarters of a cup of flaked fish.
The reason guidelines use weekly targets rather than daily ones is practical: most people eat fish as a whole meal a few times a week rather than nibbling a small amount every day. Either approach gets you to the same place nutritionally.
What the Weekly Target Actually Provides
The goal behind 2 to 3 servings per week is to deliver about 250 milligrams per day of the long-chain omega-3 fatty acids EPA and DHA. These are the fats that drive most of fish’s health benefits, particularly for the heart and brain. Two servings of fatty fish like salmon, mackerel, sardines, or herring will get you there comfortably. Leaner fish like cod, tilapia, or bass contain less omega-3 per serving, so you’d need to eat them more frequently or supplement with fattier varieties.
The American Heart Association recommends at least two servings per week, with an emphasis on fatty fish, to reduce the risk of heart failure, coronary heart disease, and stroke. For people who already have cardiovascular disease, the target is higher: roughly 1 gram of EPA and DHA daily, which generally means eating fatty fish most days or using a supplement.
How Fish Type Changes the Math
Not all fish contribute equally. A 3-ounce serving of farmed salmon delivers about 1.4 grams of EPA and DHA combined, meaning just two servings a week far exceeds the minimum omega-3 target. Wild salmon is similar, with roughly 1.2 grams per serving. Sardines and mackerel are in the same league.
Shellfish count toward your weekly total but provide less omega-3 per serving. Three ounces of cooked shrimp delivers about 0.24 grams of EPA and DHA combined. Oysters do better, offering around 0.53 grams per serving. If shellfish makes up most of your fish intake, you’ll want to eat it more often or mix in a serving of fatty fish.
Canned light tuna is a convenient middle option, though its omega-3 content varies. Canned salmon is another affordable choice with a strong nutritional profile.
Mercury Limits and Which Fish to Favor
Mercury is the main reason you can’t just eat unlimited fish. The EPA’s safe threshold for methylmercury is 0.1 micrograms per kilogram of body weight per day. For a 150-pound person, that’s about 6.8 micrograms daily. Whether you’ll approach that limit depends entirely on which fish you choose.
Canned salmon averages just 0.014 parts per million of mercury. Canned light tuna is higher at 0.126 ppm, and canned albacore jumps to 0.350 ppm. Swordfish sits at 0.995 ppm, nearly 70 times the mercury concentration of salmon. This is why the EPA and FDA sort fish into tiers:
- Best Choices (2 to 3 servings per week): salmon, sardines, anchovies, herring, tilapia, shrimp, catfish, crab, trout, Pacific oysters, flounder
- Good Choices (1 serving per week): albacore tuna, yellowfin tuna, halibut, grouper
- Fish to avoid: swordfish, shark, king mackerel, tilefish from the Gulf of Mexico, bigeye tuna, marlin
One helpful detail: most ocean fish contain selenium, a mineral that binds to mercury and reduces its harmful effects on the brain. Research measuring the selenium-to-mercury balance found that virtually all ocean fish provide a net surplus of selenium, with two notable exceptions. Mako shark and swordfish do not consistently deliver enough selenium to offset their mercury load, which is one more reason to skip them.
Adjustments During Pregnancy
Pregnant and breastfeeding women should eat 8 to 12 ounces of low-mercury fish per week. That’s the same 2 to 3 servings, but sticking strictly to the “Best Choices” list matters more because methylmercury crosses the placenta. High mercury exposure can interfere with selenium transport to the fetus and disrupt enzymes that protect the developing brain from oxidative damage.
Children need less. The FDA recommends 2 servings per week from the “Best Choices” list, with serving sizes scaled by age: about 1 ounce for toddlers ages 1 to 3, 2 ounces for ages 4 to 7, 3 ounces for ages 8 to 10, and 4 ounces at age 11.
Farmed vs. Wild: Which Counts More?
Both farmed and wild salmon are good sources of omega-3, but the nutritional profiles differ in ways that might surprise you. Farmed salmon contains about three times as much total fat as wild salmon (18% vs. roughly 6%), so while a greater proportion of wild salmon’s fat is omega-3 (24% vs. 9% in farmed), the absolute amounts of EPA and DHA per serving are similar. Farmed salmon delivers about 0.5 grams of EPA and 0.9 grams of DHA per 100 grams. Wild salmon comes in at 0.4 and 0.8 grams respectively.
The contaminant picture also cuts against common assumptions. Norwegian data found that wild salmon had three times the mercury concentration of farmed salmon (56 vs. 18 micrograms per kilogram) and higher levels of dioxins and PCBs. All values in both wild and farmed fish fell well below regulatory safety limits. In practical terms, either type works fine toward your weekly goal.
Making It Work Day to Day
If eating fish twice a week already feels like a stretch, you’re not alone. Most Americans fall short of the recommended intake. A few strategies make it easier. Keep canned salmon or sardines in your pantry for quick meals. Frozen fish fillets cook in under 15 minutes and are typically flash-frozen at peak freshness, retaining their omega-3 content. Smoked salmon on toast or sardines on crackers counts just as much as a restaurant-quality fillet.
If you prefer to eat a small amount of fish daily rather than larger portions a few times a week, that works nutritionally. A daily ounce and a half of salmon or sardines puts you right at the weekly target. The key is consistency over time, not hitting a precise number on any single day.